In many industrial applications, such as the manufacture of foods and beverages, hard surfaces commonly become contaminated with soils such as carbohydrate, proteinaceous, and hardness soils, food oil soils and other soils. Such soils can arise from the manufacture of both liquid and solid foodstuffs. Carbohydrate soils, such as cellulosics, monosaccharides, disaccharides, oligosaccharides, starches, gums and other complex materials, when dried, can form tough, hard to remove soils, particularly when combined with other soil components such as proteins, fats, oils and others. The removal of such carbohydrate soils can be a significant problem. Similarly, other materials such as proteins, fats and oils can also form hard to remove soil and residues. Food and beverage soils are particularly tenacious when they are heated during processing. Foods and beverages are heated for a variety of reasons during processing. Also, many food and beverage products are concentrated or created as a result of evaporation.
Cleaning techniques are a specific regimen adapted for removing soils from the internal components of tanks, lines, pumps and other process equipment used for processing typically liquid product streams such as beverages, milk, juices, etc. Cleaning involves passing solutions through the system and then resuming the normal food, beverage and/or pharmaceutical process. Often cleaning methods involve a first rinse, the application of the cleaning solutions, a second rinse with potable water followed by resumed operations. The process can also include any other contacting step in which a rinse, acidic or basic functional fluid, solvent or other cleaning component such as hot water, cold water, etc. can be contacted with the equipment at any step during the process. Often the final potable water rinse is skipped in order to prevent contamination of the equipment with bacteria following the cleaning and/or sanitizing step.
Cleaning of food, beverage and/or pharmaceutical equipment often requires a complete or partial shutdown of the equipment being cleaned, which results in lost production time or compromised cleaning. There is a need therefore for improved detergent compositions and methods for cleaning such equipment. An exemplary schematic diagram of a process and equipment to be cleaned is described in U.S. Pat. No. 8,114,222, which is incorporated herein by reference in its entirety.
Alkali metal hydroxide containing detergents are often referred to as caustic detergents. Caustic detergents, along with those employing alkali metal silicates and/or metasilicates are commonly used in food and beverage applications to provide effective detergency. However, high alkalinity in the presence of hard water is problematic due to formation, precipitation and deposition of water hardness scale on treated surfaces, including for example metal, plastic, glass, rubber, etc. Therefore, water treatment components are commonly added to alkaline detergents, including for example phosphorus raw materials and other water conditioning agents.
As the use of phosphates in detergents becomes more heavily regulated, industries are seeking cost effective ways to control hard water scale formation associated with highly alkaline detergents without sacrificing cleaning performance.
Therefore, there is a need for alkaline detergent compositions for use in cleaning applications to provide adequate cleaning performance while controlling hardness scale accumulation on hard surfaces in contact with the detergent compositions. Such hard surfaces may include, for example, the interior parts of processing equipment, including that customarily found within food, beverage and pharmaceutical systems.
Accordingly, it is an objective of the claimed invention to develop alkaline detergent compositions effective for reducing and/or substantially preventing hardness scale build up on hard surfaces while maintaining effective detergency.
A further object of the invention is to provide methods for employing alkaline detergents between pHs from about 10 to about 13.5, wherein the compositions may be provided in various forms, including liquids, solids, powders, pastes and/or gels, such that use solutions may be obtained at a point of use or may be used without further dilution in the case of concentrate compositions.
A still further object of the invention is to employ mono-, bis- and oligomeric phosphinosuccinic acid (PSO) adducts and provide efficient alkaline detergency while minimizing significant hardness build up and/or accumulation on treated hard surfaces.